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| United States Patent |
6,190,437
|
|
Forsyth
|
February 20, 2001
|
Iodinated air filter
Abstract
An air filter for effectively filtering bacteria, fungi and viruses from
the air. The air filter comprising of a carrier substrate impregnated with
iodine resins effectively immobilizes and attenuates bacteria, fungi and
viruses contained in passing air. The air filter may be employed in
combination with a multi-layered air filter to provide a filter which
effectively purifies passing air of a variety of contaminants. The air
filter provides a safe and effective method for the removal of bacteria,
fungi and viruses from the air.
| Inventors:
|
Forsyth; Gary Durham (Orillia, CA)
|
| Assignee:
|
Aria Pureair Ltd. (Markham, CA)
|
| Appl. No.:
|
344115 |
| Filed:
|
June 24, 1999 |
| Current U.S. Class: |
95/90; 55/485; 55/486; 55/524; 95/116; 95/285; 96/135; 96/142; 96/154; 96/226; 210/501 |
| Intern'l Class: |
B01D 046/10; B01D 053/04 |
| Field of Search: |
95/90,136,273,274,285
96/108,134-142,154,223,226,FOR 170
210/501
55/485,486,495,522,524,528
|
References Cited
U.S. Patent Documents
| 3230033 | Jan., 1966 | Hamilton et al. | 96/226.
|
| 3429103 | Feb., 1969 | Taylor | 210/501.
|
| 3817860 | Jun., 1974 | Lambert et al. | 210/501.
|
| 3923665 | Dec., 1975 | Lambert et al. | 210/501.
|
| 4238477 | Dec., 1980 | Lambert et al. | 210/501.
|
| 4312647 | Jan., 1982 | Tsuchiya et al. | 96/154.
|
| 4483771 | Nov., 1984 | Koch | 210/501.
|
| 4604110 | Aug., 1986 | Frazier | 95/136.
|
| 5015451 | May., 1991 | Holter et al. | 95/90.
|
| 5176836 | Jan., 1993 | Sauer et al. | 210/501.
|
| 5240478 | Aug., 1993 | Messina | 95/273.
|
| 5269919 | Dec., 1993 | von Medlin | 210/501.
|
| 5288298 | Feb., 1994 | Aston | 96/226.
|
| 5390668 | Feb., 1995 | Lehman | 96/108.
|
| 5529609 | Jun., 1996 | Gooch et al. | 95/90.
|
| 5554288 | Sep., 1996 | Rydell et al. | 210/501.
|
| 5558158 | Sep., 1996 | Elmore | 95/273.
|
| 5591350 | Jan., 1997 | Piechocki et al. | 210/501.
|
| 5772738 | Jun., 1998 | Muraoka | 96/154.
|
| 5874052 | Feb., 1999 | Holland | 96/226.
|
| 5876489 | Mar., 1999 | Kunisaki et al. | 96/226.
|
Primary Examiner: Spitzer; Robert H.
Claims
What is claimed is:
1. A method of purifying air, said method comprising of passing
contaminated air through a filter unit; wherein said filter unit includes
a particulate immobilizing medium; an iodinated resin substrate; and a
zeolite composite medium.
2. A multi-layered air filter for use in purifying air of a variety of
contaminants, said air filter comprised of:
a particulate immobilizing medium;
an iodinated resin substrate; and
a zeolite composite medium.
3. The multi-layered air filter of claim 2 wherein said iodinated resin
substrate comprises of a carrier substrate impregnated with iodine resins
which serve to filter bacteria, fungi and viruses from the air passing
therethrough.
4. An air purification unit for insertion in an air flow system,
comprising:
a housing having an air inlet and an air outlet; and
a multi-layered air filter proximate said air outlet;
wherein said multi-layered air filter includes a particulate immobilizing
medium, an iodinated resin substrate and a zeolite composite medium.
5. The air purification unit of claim 4 further comprising a filtering
medium proximate said air inlet.
6. The air purification unit of claim 4 or 5 further including a mid-stream
zeolite composite filter arrangement.
7. An air purification system comprising:
a housing having an air inlet and an air outlet;
an air intake means in connection with said housing for drawing air into
said air inlet and subsequently forcing air to exit said housing at said
air outlet; and
a multi-layered air filter proximate said air outlet;
wherein said multi-layered air filter includes a particulate immobilizing
medium, an iodinated resin substrate and a zeolite composite medium.
8. The air purification medium of claim 7 further comprising:
a mid-stream zeolite composite filter arrangement.
9. The air purification system of claim 7 or 8 further comprising a
filtering medium proximate said air inlet.
Description
FIELD OF THE INVENTION
The present invention provides a novel air filter for effectively providing
purified air. The air filter of the present invention is particularly
effective in the removal of bacteria, fungi and viruses from the air.
BACKGROUND
The progress of the industrialized world has not come without consequence.
In recent decades, there has been a global increase in the incidence of
disease, as well as a rapid deterioration in the health of our
environment. As we approach the 21.sup.st century, many of us look for
ways to control the quality of the environment in which we live, including
the air we breath, the water we drink and the nutritional value of our
food.
The quality of the air we breath is particularly concerning, as we require
a continual source of oxygen to ensure our survival. For the most part, we
are unaware of the potential dangers of the air we breath because some of
the most harmful substances we encounter are in the form of colourless,
odourless gases and microscopic organisms and particulate.
correlation with the demand for improved air quality in homes, offices and
institutions worldwide, many air purification devices have appeared in the
global marketplace. However, the limitation of such devices has been in
both the removal and neutralization of viruses, fungi and bacteria from
the air. Thus, there appears to be an unmet demand for an air filter with
improved purification capabilities, particularly with respect to the
removal of viruses, fungi and bacteria from the air. In addition, there is
a need for such an improved air filter which effectively attenuates the
viruses, fungi and bacteria with which it comes into contact, so as to
provide an air filter which is easily and safely discarded after use.
Further still, there is increasing demand for such a filter which is
economically feasible for general use in homes and offices.
SUMMARY OF THE INVENTION
The present invention is directed to a novel air filter for effectively
providing purified air. The present invention is particularly effective in
removing bacteria, fungi and viruses from the air.
In accordance with one aspect of the present invention there is provided an
air filter for use in purifying air of bacteria, fungi and viruses; said
air filter comprised of a carrier substrate impregnated with iodine
resins. No proprietary right is claimed in a single substrate impregnated
with an iodinated resin.
In accordance with another aspect of the present invention there is
provided a multi-layered air filter for use in purifying air of a variety
of contaminants, said air filter comprised of a particulate immobilizing
medium; an iodinated resin substrate; and a zeolite composite medium.
In accordance with another aspect of the present invention there is
provided an air purification unit for insertion in an air flow system,
comprised of a housing having an air inlet and an air outlet; and a
multi-layered air filter proximate said air outlet; wherein said
multi-layered air filter includes a particulate immobilizing medium, an
iodinated resin substrate and a zeolite composite medium.
In accordance with a further aspect of the present invention there is
provided an air purification system comprised of a housing having an air
inlet and an air outlet; an air intake means in connection with said
housing for drawing air into said air inlet and subsequently forcing air
to exit said housing at said air outlet; and a multi-layered air filter
proximate said air outlet; wherein said multi-layered air filter includes
a particulate immobilizing medium, an iodinated resin substrate and a
zeolite composite medium.
In accordance with yet another aspect of the present invention there is
provided a method of removing viruses, fungi and bacteria from air; said
method comprising of passing contaminated air through an iodinated resin
substrate, wherein iodine resins are impregnated into a permeable carrier
substrate.
In accordance with yet a further aspect of the present invention there is
provided a method of purifying air, said method comprising of passing
contaminated air through a filter unit; wherein said filter unit includes
a particulate immobilizing medium; an iodinated resin substrate; and a
zeolite composite medium.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and further advantages of this invention will be seen in reading
the description of the preferred embodiments together with reference to
the drawings, wherein:
FIG. 1 is a sectional view of an air filter arrangement of the present
invention.
FIG. 2 is a sectional view of an air filter of the present invention.
FIG. 3 is a sectional view of an air filter in accordance with an
embodiment of the present invention.
FIG. 4 is a sectional view of an air filtering apparatus in accordance with
an embodiment of the present invention.
FIG. 5 is a sectional view of an air filtering apparatus in accordance with
another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As the world's population increases, so too does industrialism, resulting
in an exponential growth in overall production. Unfortunately, this growth
is inadvertently accompanied by pollution, which contaminants our planet,
and particularly, the air we breath. With each breath we take, we not only
inhale gases which are critical to our existence, but also particles of
dust and debris, vapourized chemicals and microscopic organisms including
bacteria, viruses and fungi. Accordingly, the challenge to provide a
multi-faceted air filter is complex as each group of contaminants displays
unique physical and chemical properties.
The present invention is directed to a novel air filtering medium having
superior effectiveness in the attenuation of airborne bacteria, fungi and
viruses. FIG. 1 illustrates a filter unit 10 comprising of filter plates
12, 14 and 20. The filter plates 12, 20 and 14 are respectively positioned
in a parallel layered arrangement by brackets 16. In such an arrangement,
filter unit 10 may be easily inserted into a variety of filtering systems,
as discussed below. Further, filter unit 10 of the present invention is
not limited in size or shape and may be customized for incorporation at a
variety of locations within many ventilation and filtration systems.
Filter unit 10 is shown to include three differentiating filter plates 12,
14 and 20 each of which function to remove a particular contaminant group
from the air. Filter plate 12 is provided to trap particles of dust and
debris as air flows through filter unit 10. Filter plate 12 generally
comprises of a polypropylene composite matrix, which is known in the art
of filtration mediums to effectively trap particles in the range of sizes
of most airborne particulate. Filter plate 12 may be formed from other
industry standard materials known to effectively filter particulate of
this kind. Filter plate 14 comprises of a zeolite impregnated medium to
effectively remove odour and unwanted gases from passing air. It would
also be within the scope of this invention to replace this medium with an
equally effective industry standard alternative. Filter plate 20 is shown
to displace filter plates 12 and 14 and is comprised of an iodinated resin
substrate which effectively attenuates airborne bacteria, fungi and
viruses. The construction of filter plate 20 is shown in more detail in
FIG. 2.
In accordance with the present invention it has been discovered that iodine
resins 18 effectively immobilize and attenuate airborne bacteria, fungi
and viruses (Tables 1-2). Accordingly, by impregnating a permeable carrier
substrate 24 with iodine resins 18, it is possible to provide a filter
plate 20, as shown in FIG. 2, which is capable of effectively filtering
microbial components from passing air. The carrier substrate 24 may be a
permeable nylon such as the female member of Velcro.TM., or another
suitable carrier which effectively adheres resins of iodine. The ability
of the iodinated resin substrate to immobilize and attenuate bacteria,
fungi and viruses further provides a safe and convenient filter medium
that can be easily removed from a filtration or ventilation system and
discarded without the fear of residual contamination. Further still, the
present invention provides an economically efficient filter medium which
is disposable, and provides for quick and easy replacement.
Filter plate 20 may be impregnated with iodine resins 18 on one or both
sides of the substrate carrier 24. Optimally, a 100% saturation of iodine
resins on substrate carrier 24 is achieved for a one-sided filter plate
20. Similarly, in the case of a two-sided filter plate 20, a 200%
saturation of the substrate carrier 24 is preferred. However, effective
filtration of bacteria, fungi and viruses may be achieved at saturation
points of less than these preferred levels.
FIG. 5 illustrates the embodiment of the present invention where filter
plate 20 is impregnated with iodine resins on two sides. In accordance
with this embodiment, the capacity of the filter plate 20 may be
increased. Iodine resins 18 of both embodiments of filter plate 20, as
depicted in FIGS. 2 and 5, may be impregnated onto carrier substrates 24
of the appropriate size and shape by processes of sublimation, diffusion
or direct contact, which are well-known in the art of immobilizing resins.
In this manner, iodine resins 18 are securely adhered to a carrier
substrate 24 and can be utilized in combination with other filter mediums
to provide high-efficiency filter units, such as filter unit 10 as
illustrated in FIG. 1. Alternatively, filter plates 20 may be easily
inserted into a location about an existing ventilation or filtration
system. The present invention is not limited to a particular combination
of filter plate 20 with other effective filtering mediums or apparatuses.
When filter plate 20 is used in combination with filter plates 12 and 14 to
provide filter unit 10, passing air is first depleted of its airborne
particulate by filter plate 12. Subsequently, airborne microbes, including
bacteria, fungi and viruses adhere to iodine resins 18 of filter plate 20
and become attenuated in the presence of this metallic halogen. Finally,
the air passes through filter plate 14 which absorbs odour and other
foreign gaseous substances, such as CO.sub.2. As a result, air is
effectively purified after passing through filter unit 10.
As mentioned above, filter unit 10 or filter plate 20 alone, may be
incorporated into a variety of air purification systems and apparatuses
without being devoid of the present invention. One such system, which is
in accordance with an embodiment of the present invention, is depicted in
FIG. 3. Air purification system 40 comprises of a housing 30 having an air
inlet 28 and an air outlet 38. Housing 30 includes an air intake means 32
secured to mounting 34 between the air inlet 28 and the air outlet 38,
which serves to draw air in through air inlet 28 and subsequently force
the air through air outlet 38, past filter unit 10. The air intake means
32 may be, for example, a standard fan driven by a mechanical motor 37, in
connection with a power source 35. Alternatively, air purification system
40 may be devoid of an air intake means 32 and employed as a filtering
system which is inserted into an existing air flow system. For example, in
the absence of an air intake means 32, the air purification system 40 may
be inserted at a location within an existing air flow system within an
office building or a home so as to provide air purification.
In accordance with the air purification system 40, depicted in FIG. 3, an
air filter 36 is retrofitted along air inlet 28 and acts as a mechanical
barrier to particulate in the incoming air. In addition, a filter unit 10,
as described above, is located in the region of the air outlet 38 to
provide the air purification system 40 with a means for high-efficiency
air filtration. Air intake means 32 is situated within housing 30 to draw
air through the air inlet 28 and into the housing 30, and subsequently
force the air out the air outlet 38. In doing so, the air is filtered by
air filter 36, and filter plates 12, 20 and 14. In accordance with this
embodiment of the present invention, there is provided a high-efficiency
air filtration system which is capable of purifying air of particulate,
unwanted gases, odour and bacteria, fungi and viruses.
FIG. 4 illustrates yet another embodiment of the present invention where an
additional filtering medium 45 is provided in air purification system 40.
In the presence of this additional filter medium 45 the air purification
system 40 is capable of further elimination of residual gases and odour
from the air. Air purification system 40, as depicted in FIG. 4, is
similar in construct to the system 40 of FIG. 3. Filter medium 45 is
positioned within housing 30 and defines first and second passages 42 and
44. In this location, filter medium 45 serves to remove odour and residual
gases before the passing air reaches filter unit 10. Filter medium 45
extends across the inner dimensions of housing 30 and includes a
predetermined volume of refined zeolite evenly distributed throughout.
Alternatively, filter medium 45 may comprise of first and second permeable
walls 46 and 48 with an appropriate volume of refined zeolite displaced
there between. Where a filter medium 45 is provided in housing 30, air is
drawn through air inlet 28 by air intake means 32 and into the first
passage 42, and subsequently passes through filter medium 45 into the
second passage 44, reaching filter unit 10 as it proceeds to be forced
through air outlet 38.
The above description of the embodiments of the present invention, taken in
conjunction with the following scientific support, disclose the capability
of the present invention. As previously mentioned, the air filter of the
present invention, namely the iodinated resin substrate, is not limited by
the embodiments described above. It is herewith fully contemplated that
the iodinated resin filter of the present invention has a multitude of
applications in the art of air purification and filtration.
EXAMPLE 1
MS2 Bacteriophage
MS2 Bacteriophage were employed as the test organism in the investigation
of the iodinated resin substrate of the present invention as an effective
filtering medium for bacteria, fungi and viruses. MS2 bacteriophage belong
to a group of viruses which contain RNA as the genetic material and whose
hosts are bacteria. This virus is approximately 26 to 27 nm in diameter
and is icosahedral in shape. This virus is particularly useful for
laboratory experimentation as it only infects male strains of Escherichia
coli. Several other useful characteristics of MS2 bacteriophage include
their high rate of replication (causing lysis of the bacterium in 30-40
minutes) and a high yield of infectious progeny particles (approximately
10,000 per cell). MS2 bacteriophage have been used in disinfection
efficacy experiments as a surrogate for polio viruses, enteroviruses and
other more serious human pathogenic RNA viruses, because of its size,
shape and nucleic acid composition. Accordingly, MS2 bacteriophage was
considered a representative test organism for the purpose of testing the
filtering capabilities of the iodinated resin substrate of the present
invention.
Experimental Design
The testing of the impregnated resin substrate of the present invention was
constructed such that accurate measurements of particulate reduction could
be obtained on a volume of air basis. Initially, a 1.0 m.sup.3 unit
including a fan, was attached to the iodinated resin substrate of the
present invention and the air flow exiting the filter unit was measured at
both high and low speeds (High=1.0 m.sup.3 /min, Low=0.2 m.sup.3 /min).
Test samples of MS2 bacteriophage were aliquoted at a concentration of
10.sup.10 PFU/ml. Sterile water samples were used as negative controls.
Subsequently, MS2 bacteriophage aliquots were introduced into the filter
unit in atomized form (to provide the positive samples), and the filter
unit was then sealed with the iodinated resin substrate. The outflowing
air was sampled for 10 minutes at 12.5 L per minute (representing 0.125
m.sup.3 of air). A glass impinger containing TYGB broth was used in
sampling the air.
Samples
MS2 bacteriophage were introduced in a freshly disinfected unit which was
subsequently sealed with filters as outlined above. The filter unit ran
for 5 minutes at a low setting (representing a sample of 1.0 m.sup.3 of
air). The filter unit was then turned off and the glass impingers
subsequently ran for an additional 10 minutes at 12.5 L per minute to
sample for residual bacteriophage. Samples of TGYB broth were removed from
the glass impingers and plated with host E. coli and the number of plaques
enumerated. On the basis of plaque formation, the reduction in MS2
bacteriophage was calculated (Table 1).
Results
The results of the experimentation described above indicated that the
iodinated resin substrate was capable of significantly reducing airborne
bacteriophage levels. As illustrated in Table 1, the iodinated resin
substrate of the present invention obtained up to 88.10% reduction in
airborne bacteriophage content. Negative control samples indicated that
there was no MS2 bacteriophage present in the unit prior to the
introduction of aliquoted MS2 samples.
TABLE 1
Results of MS2 Bacteriophage Reduction Experiment.
Start Start End End Phage %
Date Sample Temp. RH Temp. RH PFU/m.sup.3
Reduction
10-04-99 Neg. Control 22.degree. C. 55% 22.degree. C. 60% <1000
Neg. Control 21.degree. C. 43% 21.degree. C. 68% <1000
12-04-99 Pos. Control 21.degree. C. 31% 21.degree. C. 51% 5.6
.times. 10.sup.9 70.00%
Filter Run 21.degree. C. 51% 21.degree. C. 70% 1.68
.times. 10.sup.9
15-04-99 Pos. Control 24.degree. C. 32% 24.degree. C. 47% 3.696
.times. 10.sup.9 88.10%
Filter Run 24.degree. C. 35% 24.degree. C. 44% 4.400
.times. 10.sup.8
16-04-99 Pos. Control 22.degree. C. 36% 22.degree. C. 66% 6.16
.times. 10.sup.9 84.00%
Filter Run 22.degree. C. 54% 22.degree. C. 76% 9.84
.times. 10.sup.8
19-04-99 Pos. Control 22.degree. C. 50% 22.degree. C. 72% 1.44
.times. 10.sup.9 57.78%
Filter Run 22.degree. C. 44% 22.degree. C. 67% 6.08
.times. 10.sup.8
Pass Through 1.36 .times.
10.sup.8
AVERAGE 22.1.degree. C. 43% 22.1.degree. C. 62%
75%
Upon completion of the reduction experiment discussed above, the iodinated
resin substrate was removed from the filter unit and any residual
bacteriophage were eluted off the resin into TYGB broth. The eluted sample
was then introduced to host-containing plates and viable MS2 bacteriophage
were enumerated by plaque counts (Table 2).
TABLE 2
MS2 Bacteriophage viability counts from eluted resin.
Viable Viable
MS2 MS2 MS2 Exposed Log %
PFU/ml PFU/filter PFU/filter Attenuated Attenuation
Sample 29 2900 1.318 .times. 10.sup.10 6.658 99.9999
1
Sample 29 2900 1.318 .times. 10.sup.10 6.658 99.9999
2
The results of the viability plating indicated that a 6.658 log reduction
in MS2 bacteriophage viability was achieved by the iodinated resin
substrate. This translated into a 99.9999% attenuation of MS2
bacteriophage over the duration of the experiment.
Conclusions
The success of the iodinated resin substrate of the present invention to
immobilize and attenuate MS2 bacteriophage from the air is an indication
of the potential of such a substrate to be incorporated in a variety of
air filtration systems for the safe and effective removal of bacteria,
fungi and viruses from the air. The use of MS2 bacteriophage in the
experimentation described above was deliberately chosen as a
representative organism for all potentially hazardous airborne microbes.
On the basis of the well known resistance of such viruses against a
variety of disinfectants, the discovery of the effectiveness of the
iodinated resin substrate (as described and illustrated as filter plate
20--FIGS. 1-3) against MS2 bacteriophage is herewith held with confidence
to be a further indication that the iodinated resin substrate of the
present invention is similarly effective against other viruses, bacteria
and fungi.
It is believed that the percentage reduction in airborne microbes can be
increased with the employment of the present invention, with improvements
to the fan incorporated within the unit described above. In addition,
further investigation is required to determine the optimal life time of
the iodinated resin substrate.
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